Load-Invariant Configuration of Interference Measurement Resources

1. A method at a node in a wireless communication network that is configured for Coordinated Multi-Point (CoMP) operation, said method comprising configuring one or more transmission points in a set of CoMP transmission points on a dynamic basis, with respect to one or more defined Interference Measurement Resources (IMRs), including configuring a first transmission point to follow a first rule according to which the first transmission point: transmits on at least one of the IMRs, if the first transmission point is deemed as being not likely to transmit data at a time relevant to the at least one IMR; and does not transmit on the at least one IMR, if the first transmission point is deemed as being likely to transmit data at a time relevant to the at least one IMR.

2. The method of claim 1 , wherein configuring the one or more transmission points further comprises configuring a second transmission point to follow a second rule according to which the second transmission point: transmits on at least one of the IMRs, if the second transmission point is deemed as being likely to transmit data at a time relevant to the at least one IMR; and does not transmit on the at least one IMR, if the second transmission point is deemed as being not likely to transmit data at a time relevant to the at least one IMR.

3. The method of claim 2 , wherein the first and second transmission points comprise: the same transmission point taken at different times, or taken with respect to different ones of the IMRs; or different transmission points configured with respect to the same at least one IMR.

4. The method of claim 1 , further comprising maintaining one or more control variables, where each control variable indicates whether a corresponding one or ones of the transmission points is deemed as being likely or not likely to transmit data at a time relevant to a respective one or ones of the IMRs, including for each control variable, dynamically setting the control variable to: a first state if the corresponding one or ones of the transmission points is deemed as being likely to transmit data at a time relevant to the respective one or ones of the IMRs; or a second state if the corresponding one or ones of the transmission points is deemed as being likely to transmit data at a time relevant to the respective one or ones of the IMRs, wherein the first and second states are complementary.

5. The method of claim 4 , further comprising determining whether any given transmission point is deemed as being likely or not likely to transmit data at a time relevant to any given IMR, based on reading the value of the control variable maintained with respect to the given IMR and the given transmission point.

6. The method of claim 1 , wherein the configuring step comprises: for at least one of the IMRs, logically dividing the set of CoMP transmission points into first and second subsets; where each transmission point in the first subset is configured to transmit or not transmit on the IMR according to the first rule; and where each transmission point in the second subset is configured to transmit or not transmit on the IMR according to the second rule.

7. The method of claim 1 , further comprising, for any given transmission point in the set of CoMP transmission points: deeming the transmission point as being likely to transmit data at a time relevant to a given IMR based on the fulfilment of a set of any one or more of the following traffic activity and/or loading conditions: determining that downlink data is transmitted from the transmission point on relevant frequencies; determining that there is data in a downlink transmission buffer of the transmission point; determining that the transmission point is serving as a primary transmission point for one or more active wireless devices operating in the wireless communication network; and determining that a loading level of the transmission point is above a defined upper loading threshold; and otherwise, when the set of any one or more of the traffic activity and/or loading conditions is not fulfilled, deeming the transmission point as being not likely to transmit data at the time relevant to the given IMR.

8. The method of claim 7 , further comprising setting a corresponding control variable to a first state if the transmission point to indicate that the transmission point is deemed as being likely to transmit data at the time relevant to the given IMR, or setting the corresponding control variable to a second state to indicate that the transmission point is deemed as being not likely to transmit data at the time relevant to the given IMR, wherein the first and second states are complementary.

9. The method of claim 8 , further comprising performing said steps of deeming and setting on a repeating basis, so that whether a given transmission point is deemed as being likely or not likely to transmit data at a time relevant to a given IMR changes as a function of changing conditions at the transmission point and/or in the wireless communication network, and so that the deemed state of the given transmission point for the given IMR changes according to the changing conditions.

10. The method of claim 1 , further comprising deeming any given transmission point in the set of CoMP transmission points as being likely to transmit data at a time relevant to a given one of the IMRs if there is a possibility of such a data transmission from the given transmission point, and otherwise deeming the given transmission point as being not likely to transmit data at a time relevant to the given IMR.

11. The method of claim 1 , further comprising configuring a wireless device supported by one or more of the transmission points in the set of CoMP transmission points to feed back a Channel State Information (CSI) report based on measuring interference on the at least one IMR.

12. The method of claim 11 , wherein the CSI report is configured to use a rank indicator (RI) and/or precoder matrix indicator (PMI) that is equal to the respective RI and/or PMI from another CSI report that the wireless device is configured to feed back.

13. The method of claim 1 , further comprising performing the step of configuring on a group-wise basis, so that a group of transmission points from the CoMP set of transmission points act collectively with respect to the at least one IMR and either all transmit on the at least one IMR or all do not transmit on the at least one IMR, based on configuring the group to follow the second rule, wherein: all transmission points in the group transmit on the at least one IMR, if any of the transmission points in the group is deemed as being likely to transmit data at a time relevant to the at least one IMR; or none of the transmission points in the group transmit on the at least one IMR, if all of the transmission points in the group are deemed as being not likely to transmit data at a time relevant to the at least one IMR.

14. A node in a wireless communication network that is configured for Coordinated Multi-Point (CoMP) operation, said node comprising: a communication interface configured for communicating with transmission points in a set of CoMP transmission points; and one or more processing circuits operatively associated with the communication interface and configured to configure one or more of the transmission points on a dynamic basis, with respect to one or more defined Interference Measurement Resources (IMRs) including configuring a first transmission point to follow a first rule according to which the first transmission point: transmits on at least one of the IMRs, if the first transmission point is deemed as being not likely to transmit data at a time relevant to the at least one IMR; and does not transmit on the at least one IMR, if the first transmission point is deemed as being likely to transmit data at a time relevant to the at least one IMR.

15. The node of claim 14 , wherein the one or more processing circuits are further configured to configure a second transmission point to follow a second rule according to which the second transmission point: transmits on at least one of the IMRs, if the second transmission point is deemed as being likely to transmit data at a time relevant to the at least one IMR; and does not transmit on the at least one IMR, if the second transmission point is deemed as being not likely to transmit data at a time relevant to the at least one IMR.

16. The node of claim 15 , wherein the first and second transmission points comprise: the same transmission point taken at different times, or taken with respect to different ones of the IMRs; or different transmission points configured with respect to the same at least one IMR.

17. The node of claim 14 , wherein the one or more processing circuits are configured to maintain one or more control variables, where each control variable indicates whether a corresponding one or ones of the transmission points is deemed as being likely or not likely to transmit data at a time relevant to a respective one or ones of the IMRs, based on being configured to, for each control variable, dynamically set the control variable to: a first state if the corresponding one or ones of the transmission points is deemed as being likely to transmit data at a time relevant to the respective one or ones of the IMRs; or a second state if the corresponding one or ones of the transmission points is deemed as being likely to transmit data at a time relevant to the respective one or ones of the IMRs, wherein the first and second states are complementary.

18. The node of claim 17 , wherein the one or more processing circuits are configured to determine whether any given transmission point is deemed as being likely or not likely to transmit data at a time relevant to any given IMR, based on reading the value of the control variable maintained with respect to the given IMR and the given transmission point.

19. The node of claim 14 , wherein the one or more processing circuits are configured to: for at least one of the IMRs, logically divide the set of CoMP transmission points into first and second subsets; where each transmission point in the first subset is configured to transmit or not transmit on the IMR according to the second rule; and where each transmission point in the second subset is configured to transmit or not transmit on the IMR according to the first rule.

20. The node of claim 14 , wherein, for any given transmission point in the set of CoMP transmission points, the one or more processing circuits are configured to perform a deeming operation in which the one or more processing circuits: deem the transmission point as being likely to transmit data at a time relevant to a given IMR based on the fulfilment of a set of any one or more of the following traffic activity and/or loading conditions: determining that downlink data is transmitted from the transmission point on relevant frequencies; determining that there is data in a downlink transmission buffer of the transmission point; determining that the transmission point is serving as a primary transmission point for one or more active wireless devices operating in the wireless communication network; and determining that a loading level of the transmission point is above a defined upper loading threshold; and otherwise, when the set of any one or more of the traffic activity and/or loading conditions is not fulfilled, deem the transmission point as being not likely to transmit data at the time relevant to the given IMR.

21. The node of claim 20 , wherein the one or more processing circuits are configured to perform the deeming operation on a repeating basis, so that the status of the transmission point as being deemed likely or not likely to transmit data at the time relevant to the given IMR changes dynamically with changes in loading at the transmission point and/or within the wireless communication network.

22. The node of claim 14 , wherein the one or more processing circuits are configured to deem any given transmission point in the set of CoMP transmission points as being likely to transmit data at a time relevant to a given one of the IMRs, if there is a possibility of such a data transmission from the given transmission point, and otherwise to deem the given transmission point as being not likely to transmit data at a time relevant to the given IMR.

23. The node of claim 14 , wherein the one or more processing circuits are configured to configure a wireless device supported by one or more of the transmission points in the set of CoMP transmission points to feed back a Channel State Information (CSI) report based on measuring interference on the at least one IMR.

24. The node of claim 23 , wherein the CSI report is configured to use a rank indicator (RI) and/or precoder matrix indicator (PMI) that is equal to the respective RI and/or PMI from another CSI report that the wireless device is configured to feed back.

25. The node of claim 14 , wherein the one or more processing circuits are configured to configure the transmission points in the set of CoMP transmission points on a group-wise basis so that a group of transmission points from the CoMP set of transmission points act collectively with respect to the at least one IMR and either all transmit on the at least one IMR or all do not transmit on the at least one IMR, based on configuring the group to follow the second rule, wherein: all transmission points in the group transmit on the at least one IMR, if any of the transmission points in the group is deemed as being likely to transmit data at a time relevant to the at least one IMR; or none of the transmission points in the group transmit on the at least one IMR, if all of the transmission points in the group are deemed as being not likely to transmit data at a time relevant to the at least one IMR.